Cutter bit grinder

ABSTRACT

Apparatus for grinding the steel portion of a steel and carbide cutter bit includes a bit holder, a support for moving said bit holder between a loading position away from a grinding wheel and a grinding position wherein the bit is pressed against the wheel.

United States Patent Sollami Aug. 26, 1975 [5 CUTTER BIT GRINDER2,246,023 6/1941 Spurling 51/218 R [76] Inventor: Phillip A. Sollami,438 Sherman St., 3 311 32 33:5, 5 ,1

Downers Grove, 60515 2,988,858 6/1961 Bass 51/1659 x Pettee X Appl. No.:398,064

U.S.Cl ..51/98 BS;5l/2l5 UE',51/218R Int. Cl B24b 3/36 Field of Search51/98 R, 98 BS, 98.5, 125, 51/1255, 215 CP, 215 UE, 218 R, 91 R, 91 BS,224, 230, 94, 165.9, 96, 234; 269/94 References Cited UNITED STATESPATENTS 6/1939 Bower 51/234 Primary Examiner-Al Lawrence Smith AssistantExaminerNicholas P. Godici Attorney, Agent, or Firm-Edmond T. Patnaude 57] ABSTRACT 7 Claims, 4 Drawing Figures CUTTER BIT GRINDER The presentinvention relates in general to grinding apparatus of the type employinga rotating grinding wheel and a work piece holder, and it relates moreparticularly to semiautomatic apparatus for grinding the steel portionof a carbide cutter bit used in the coal mining industry.

BACKGROUND OF THE INVENTION The cutter bit most commonly used in thecoal mining industry consists of a carbide cutting tip held in a steelholder. Frequent sharpening of the bits is necessary, and the sharpeningoperation entails the grinding of both the carbide tip and the adjacentportion of the steel holder. The grinding operation is generally done byhand which is both tedious and hazardous and which results ininconsistently sharpened cutter bits. Moreover, because of the differentcharacteristics of the carbide and the steel, the use of a singlegrinding wheel for removing the carbide and the steel is extremelyinefficient and results in short wheel life. The use of composite wheelshaving adjacent portions for respectively grinding the steel and thecarbide has increased wheel life but the quality of the sharpened bitshas not been improved.

OBJECTS OF THE INVENTION In order to enable the sharpening of cutterbits in a safe and economical manner while producing sharpened bits ofconsistently high quality and shape, a principal object of the presentinvention is to provide semiautomatic grinding apparatus which moves amanually fed bit holder between a loading position remote from thegrinding wheel and an adjustable preset grinding position where it isurged under fluid pressure for a predetermined period of time againstthe edge of a grinding wheel to grind the steel portion only of the bit.The carbide tip is ground in a separate operation.

Another object of the present invention is to provide a novel cutter bitholding fixture which enables the rapid, safe and facile loading of thebits by a relatively unskilled operator.

A further object of this invention is to provide semiautomatic cuttingbit sharpening apparatus which can be manufactured at a sufficiently lowprice to be competitively marketed.

SUMMARY OF THE INVENTION The above and further objects may be realizedin accordance with the present invention by providing a cutter bitholding fixture adjustably mounted on an upright member which ispivotably mounted on a base plate re ciprocably mounted for rectilinearmovement in a direction parallel to the plane of the associate grindingwheel. The upright member pivots about an axis perpendicular to theplane of the wheel thereby to swing the bit holder to the side of thewheel to facilitate loading of a bit therein. The upright is pivoted bymeans of a fluid operated piston and cylinder, and the base plate isreciprocated by a fluid operated piston and cylinder which also pushesthe bit against the grinding wheel with a predetermined force. Controlmeans coordinates the actuation of the two cylinders and of a clampingmechanism in the bit holder to urge the bit against the grinding wheelfor a predetermined time whereby successive bits are ground tosubstantially the same configuration.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages and abetter understanding of the invention may be had from the followingdetailed description taken in connection with the accompanying drawings,wherein:

FIG. 1 is an elevational view of a cutter bit grinding apparatusembodying the present invention;

FIG. 2 is a partially sectioned view of the apparatus of FIG. 1 takenalong the line 22 thereof;

FIG. 3 is a plan view of the holding fixture portion of the machine ofFIG. 1 taken from the line 33 thereof; and

FIG. 4. is a sectional view taken along the line 44 of FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to the drawings andparticularly to FIGS. 1 and 2 thereof, a machine 10 for grinding thesteel portions of cutter bits comprises a base plate 11 to which a pairof brackets 12 and 13 are fixedly secured as by welding. The brackets 12and 13 include flange portions 12a and 13a lying at an angle of 45 andto which a pair of channel shaped guide rails 14 and 15 are secured. Asupport plate 16 is slidably connected to the rails 14 and 15 by fourroller bushings 17 threadedly mounted to the side edges of the plate 16by studs 18. The studs 18 also lie at an angle of 45 whereby the rails14 and 15 prevent both vertical and lateral movement of the plate 16relative to the base plate 11 while permitting horizontal movementthereof along an axis parallel to the plane of a grinding wheel 19. Apneumatic or hydraulic cylinder 22 is mounted between the plates 11 and16 by a pair of clevices 23 and 24 for reciprocably moving the plate 16in a horizontal direction in the guide rails 14 and 15.

Mounted to the top of the plate 16 is a pair of pillow blocks 25 and 26in which a horizontal shaft 27 is journaled by suitable sphericalbearings 30. An upright member or post 28 is fixedly mounted to theshaft 27 by a sleeve 29 welded to the post and press fitted onto theshaft 27. The post 18 may thus pivot in a vertical plane perpendicularto the axis of reciprocation of the plate 16. A pneumatic or hydrauliccylinder 32 is interconnected between the plate 16 and the post 28 forcontrolably pivoting the post 28 about the shaft 27. More particularly,the cylinder 32 is pivotably connected to a clevice bracket 33 welded tothe plate 16 and the piston of the cylinder 32 is pivotably connected toa lug 34 fastened to the upright near the top thereof. The uprightgrinding position of the post 28 is adjustable by means of a stop bolt35 threadly received in a lug 36 fixed to and extending from the post28.

A mounting platform 38 is fixed to the top of the post 28 by a pair ofarms 39 and 40 and a cutter bit holding fixture 43 is adjustablysupported on the plate 38 by a plurality of bolts 44 which extendthrough enlarged holes in a plate 45 and are threadedly received incorrespondingly located tapped holes in the platform 38. As best shownin FIGS. 3 and 4, the plate 45 is part of the holding fixture 43, and apair of guide strips 46 are adjustably mounted thereon by a plurality ofbolts 47 which extend through elongated openings or slots 48 in theguide strips 46. The guides 46 and the intermediate surface of the plate45 thus define a guide channel for receiving the shank of a cutter bit50.

The shank portion of the cutter bit 50 is slidably received in thechannel between the guide members 46, which channel is disposed at anangle of between and relative to the plane of the grinding wheel 19. Byproper adjustment of the guide members 45 the carbide tip portion 51 ofthe bit is positioned immediately adjacent the edge 52 of the grindingwheel 19 so that the working surface 53 of the wheel 19 engages only thesteel portion of the bit back of the carbide tip 51.

In order to clamp the bit 50 in the holding fixture, a lever arm 55 ispivotably mounted on a horizontal shaft 56 held between a pair ofbrackets 57 and 58 bolted to the plate 45. A clamping pad 59 isconnected to the forward end portion of the lever arm 55 and locked inplace by a nut 62. A ball and socket connection (not shown) is providedbetween the stud 60 and the pad 59 to permit the flat bottom surface 63of the pad to seat flat against the upper surface of the shank of thebit 50 lying on the plate 45-between the guide members 46. A fluidoperated cylinder 66 is mounted to the rearward end portion of the leverarm 55, and a push pin 67 is threadedlyconnected to the piston thereof.When the cylinder 66 is actuated to project the piston, the pin 67presses against the plate 45 to lift the rearward end of the lever arm55 and press the pad 59 against the bit 50 to clamp it against the plate45 in the guide channel. At the completion of the grinding operation thepiston is retracted in the cylinder 66 and the weight of the cylindercauses the lever to pivot in a counterclockwise direction as viewed inFIG. 4 to lift the pad 59 and release the bit. A spring loaded aircylinder 70 is mounted to the plate 45 by a bracket 71 and includes apin 72 connected to the piston for ejecting the ground bit from theholding fixture when the cylinder 70 is actuated with the pad 59 liftedoff the bit.

OPERATION The cylinders 22, 32, 66 and 70 are operated in a controlledsequence as described below by any suitable timing mechanism such, forexample, as motor driven, switch actuating cams. At the end of agrinding cycle, the pistons in all of the cylinders are in the retractedpositions whereby the plate 16 is in a fully rearward position and thepost 28 is tilted downwardly to the right as shown in FIG. 1 whereby thefront end of the holding fixture 43 is about four to six inches from theright hand face of the wheel 19.

The operator loads a bit into the fixture by sliding it between theguides 46 along the top surface of the plate 45 until a rearwardlyfacing shoulder 74 on the bit abutsthe foreward end of the left handguide member 46. This position is best illustrated in FIG. 3. Since theplate 45 lies at an angle of about 75 to the horizontal at this time,the bit will remain in the inserted position resting on the plate 45 andthe right hand guide member 46. The operator then simultaneouslyactuates two start switches, one with each hand, to initiate a grindingcycle.

Closing of the start switches energizes the timer motor which firstactuates the cylinder 66 to force the clamping pad 59 against the cutterbit to lock it in place in the fixture. The cylinders 22 and 32 areactuated at about the same time to move the cutter bit into the grindingposition directly opposite the horizontal diameter of the grindingwheel. The rate of fluid flow to the cylinders 22 and 32 is mutuallyrelated so that the post 28 reaches its fully upright grinding positionwith the end of the bolt 35abutting the plate 45 before the plate .16has moved forewardly a sufficient amount to cause the bit to engage thewheel. Continued movement of the plate 16 under the force exertedthereon by the cylinder 22 then presses the steel portion of the cutterbit against the edge of the wheel as shown in FIG. 3. The bit 50 is thuspushed at a predetermined pressure as determined by the cylinder 22against the wheel along an axis which intersects the rotational axis ofthe wheel at an angle of 90 to grind away a portion of the steeldirectly behind and adjacent to the carbide tip 51. After apredetermined grinding time as determined by the timer,the cylinder 22is actuated to move the plate 16 rearwardly thereby to retract theground bit away from the wheel 19. Shortly thereafter the cylinder 22 isactuated to swing the holding fixture downwardly to the right. Thecylinders 22 and 32 simultaneously retract the respective pistons untilthe fixture is in loading position. The cylinder 66 is then actuated toretract the piston whereby the lever arm pivots counterclockwise to liftthe pad 59 from the bit. An impulse of air is then supplied to thecylinder to sharply drive the eject pin against the rear end of thecutter bit 50 to eject it from the fixture into a suitable containerlocated below and to the right of the wheel 19. The grinding cycle isthus completed with the holding fixture stopped in the loading positionand the clamping pad elevated to permit insertion of the next bit to beground.

A complete grinding cycle from loading to ejection lasts approximatelyfour seconds with the actual grinding time being 1.5 to 2 seconds. Usingan aluminum oxide wheel having a diameter of twelve inches rotating at aspeed of 1,725 rpm and a force of between 20 and 50 lbs on the bit, agrinding period of 1.5 to 2 seconds provides sufficient steel removalfor a normal cutter bit. Where the carbide tips'have been sharpened manytimes so that the amount of steel to be removed is near a maximum, thehigher grinding force is recommended. In this respect, in normalpractice the operator will group the bits to be ground so that eachgroup can be ground without adjustment of the pressure to the cylinder22.

While the present invention has been described in connection withparticular embodiments thereof, it will be understood that those skilledin the art may make many changes and modifications without departingfrom the true spirit and scope thereof. Accordingly, the appended claimsare intended to cover all such changes and modifications as fall withinthe true spirit and scope of the present invention.

Whatl claim is:

1. semiautomatic apparatus for feeding a combination steel and carbidecutter bit against a grinding wheel for grinding the steel portion ofthe bit, comprising a base member disposed in fixed relationship to agrinding wheel,

guide rail means mounted on said base member,

a support member slidably supported by said guide rail means forreciprocable movement toward and away from said grinding wheel,

an upright member mounted to said support member for pivotablemovementin a plane perpendicular to the direction of movement of said supportmember,

a bit holding fixture mounted on said upright member,

said holding fixture including a clamp for locking said bit in saidfixture with the steel portion thereof opposite said grinding wheel,

fluid operated means for moving said support member along said railmeans, and

drive means for pivotably moving said upright member in said plane,

whereby energizing said fluid operated means and said drive means movesa bit held in said fixture to a position opposite the edge of saidgrinding wheel and then urges said bit against the edge of said grindingwheel at a predetermined force.

2. Apparatus as set forth in claim 1 wherein said fixture comprises aguide channel for receiving the shank of the bit to be ground, and saidclamp includes first means for selectively clamping said bit in saidchannel, and

selectively operated means for ejecting said bit from said channel.

3. Apparatus as set forth in claim 2 comprising means for adjusting theposition of said fixture on said upright member.

4. Apparatus as set forth in claim 2 wherein said first means comprisesa support plate,

an arm pivotably supported on said support plate,

a bit engageable clamping pad carried near one end of said arm forclamping a bit against said plate, and

a fluid operated means connected near the other end of said arm forpivoting said arm to urge said clamping pad against said bit to lock itin place in said fixture.

5. Apparatus as set forth in claim 4 wherein said slectively operatedmeans comprises a pneumatic cylinder and piston assembly.

6. In combination,

a grinding wheel mounted for rotation about a first horizontal axis,

said wheel having a generally cylindrical grinding edge and circularsides,

a fixture for holding a work piece to be ground,

support means for supporting said fixture in a grinding positionopposite said grinding edge of said wheel and in a loading positionbelow said grinding position and off to one side of said wheel,

trunnion means mounting said support means for arcuate movement about asecond axis disposed below said wheel and extending horizontally,

power operated means for angularly moving said support means about saidsecond axis to move said fixture between said grinding and loadingpositions, and

means for moving said support and said trunnion means in a horizontallinear direction toward and away from said wheel.

7. The combination set forth in claim 6 wherein said fixture comprises acutter bit receiving guide channel for holding a cutter bit at an angleof between 10 and 20 relative to the plane of said grinding wheel whensaid fixture is in said grinding position.

1. Semiautomatic apparatus for feeding a combination steel and carbidecutter bit against a grinding wheel for grinding the steel portion ofthe bit, comprising a base member disposed in fixed relationship to agrinding wheel, guide rail means mounted on said base member, a supportmember slidably supported by said guide rail means for reciprocablemovement toward and away from said grinding wheel, an upright membermounted to said support member for pivotable movement in a planeperpendicular to the direction of movement of said support member, a bitholding fixture mounted on said upright member, said holding fixtureincluding a clamp for locking said bit in said fixture with the steelportion thereof opposite said grinding wheel, fluid operated means formoving said support member along said rail means, and drive means forpivotably moving said upright member in said plane, whereby energizingsaid fluid operated means and said drive means moves a bit held in saidfixture to a position opposite the edge of said grinding wheel and thenurges said bit against the edge of said grinding wheel at apredetermined force.
 2. Apparatus as set forth in claim 1 wherein saidfixture comprises a guide channel for receiving the shank of the bit tobe ground, and said clamp includes first means for selectively clampingsaid bit in said channel, and selectively operated means for ejectingsaid bit from said channel.
 3. Apparatus as set forth in claim 2comprising means for adjusting the position of said fixture on saidupright member.
 4. Apparatus as set forth in claim 2 wherein said firstmeans comprises a support plate, an arm pivotably supported on saidsupport plate, a bit engageable clamping pad carried near one end ofsaid arm for clamping a bit against said plate, and a fluid operatedmeans connected near the other end of said arm for pivoting said arm tourge said clamping pad against said bit to lock it in place in saidfixture.
 5. Apparatus as set forth in claim 4 wherein said slectivelyoperated means comprises a pneumatic cylinder and piston assembly.
 6. Incombination, a grinding wheel mounted for rotation about a firsthorizontal axis, said wheel having a generally cylindrical grindinG edgeand circular sides, a fixture for holding a work piece to be ground,support means for supporting said fixture in a grinding positionopposite said grinding edge of said wheel and in a loading positionbelow said grinding position and off to one side of said wheel, trunnionmeans mounting said support means for arcuate movement about a secondaxis disposed below said wheel and extending horizontally, poweroperated means for angularly moving said support means about said secondaxis to move said fixture between said grinding and loading positions,and means for moving said support and said trunnion means in ahorizontal linear direction toward and away from said wheel.
 7. Thecombination set forth in claim 6 wherein said fixture comprises a cutterbit receiving guide channel for holding a cutter bit at an angle ofbetween 10* and 20* relative to the plane of said grinding wheel whensaid fixture is in said grinding position.